When two computer subsystems are connected by a bi-directional multi-bit transmission links bus (BiDi) linking two chips on a module or linking two modules within a computer system, several questions arise. They are: (1) What is the bandwidth of the link? (2) How many bits can be stored in the link during data transmission? (3) How fast one can change the BiDi direction? and (4) What is the timing/clocking relationships between two subsystems? These are not easy to answer questions.